254 
CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1904.        [bull.  26*3 
plate,  sheets,  bars,  and  manufactured  articles  probably  balance  this. 
The  zinc  industry  of  the  United  States  is  practically  independent  ol 
that  abroad,  neither  exports  nor  imports  forming  more  than  a  small 
fraction  of  production  and  consumption,  though  this  country  pro- 
duces only  a  trifle  less  than  27  per  cent  of  the  world's  supply  oJ 
spelter. 
LEAD  RESOURCES  OF  THE  UNITED  STATES. 
In  1903  the  total  lead  production  from  domestic  ores  in  the  UnitJ 
States  is  estimated  in  Mineral  Resources  a  at  280,000  short  tons,  hav- 
ing a  total  value  of  $23,520,000.  In  addition,  88,324  tons  were  ob- 
tained from  foreign  ores  smelted  within  the  country,  but  most  oJ 
this  was  offset  by  exports. 
Two  grades  of  lead  are  recognized  in  this  country.     One  is  "  sol 
lead,"  derived  from  non-argentiferous  ores,  found  mainly  in  the  Mis- 
sissippi Valley;   the  other  is  the  desilverized  lead,  coming  principally 
from  the  Rocky  Mountain  States  and  the  Great  Basin.    The  produc 
tion  by  States  for  1903  is  estimated  by  Mr.  Kirchhoff  as  below. b 
Lead  con  hut  of  ores  by  States,  1903. 
S! 
Idaho 
Utah 
Colorado 
Montana 
Nevada  
Oregon,  Alaska,  South  Dakota,  Texas 
Arizona 
New  Mexico  
Washington 
California    
Missouri.  Kansas,  Wisconsin,  Illinois,  Iowa,  Virginia,  and 
Kentucky  "soft  lead" 
tort  tons. 
99,590 
51, 129 
45,  554 
3,303 
2,  237 
1,  765 
1,493 
613 
538 
55 
86,  597 
Total  lead  content  of  ores  smelted 292,874 
Miscellaneous  or  unknown 2,831 
Data  regarding  the  past  production  of  the  United  States  are 
complete,  but  preliminary  estimates  based  on  the  best  obtainable  sta-f 
tistics  allow  the  following  approximations  to  be  made : 
Estimated  total  lead  production  of  the  United  states. 
Short  tons. 
Desilverized  load 4,300,000 
Soft  lead 1,700,000 
Total         6,000,000 
"  Minern  1  Resources  of  the  United  States,  190:>,  p.  39. 
0  Idem,  p.  243. 
